The invention concerns a device for the repair of conductor path interruptions or breaks on printed circuit boards by means of microwelding.
In the case of new generation printed circuit boards, the conductor paths no longer run in a straight line, but rather are designed meander-like in trapezoidal conductor paths. The conductor paths produced by means of etching have, for example, a height of 30 .mu.m and a width of 120 to 150 .mu.m. The base length of a trapezoid is, for example, 1.20 mm.
In the case of the manufacturing process, interruptions can arise in the conductor paths. Since the printed circuit boards after placement of components are subjected to a soldering process, the repairing of the conductor paths must be carried out with a method whereby it is assured that the repair points suffer no damage as a result of the temperature arising by means of the soldering, and that the connections do not break again. Such a method is micro-resistance welding. In the magazine Feinwerktechnik, 75, 1971, Pamphlet 5, pp. 201-206, incorporated herein by reference, a method is described whereby through means of micro-resistance welding with a constant voltage device and gap electrodes with the use of nickel strips or wires, constricted or broken conductor paths are repaired on through-connection printed circuit boards.
In the case of straight conductor paths, the interruption was bridged by means of a suitable repair strip which was soldered on at both sides of the interruption one after the other by means of emplacement electrodes. The positioning thereby proceeded by means of a separate suction nozzle which was removed after the production of the first spot weld.